s390/dasd: Move allocation error message to DBF

s390/dasd: Move allocation error message to DBF

All error messages for a failling dasd_smalloc_request() call are logged
via DBF, except one. There is no value in logging this particular
allocation failure via dev_err(). Move the message to DBF, too, to be
in line with the rest.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240208164248.540985-5-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>